The trinomialsx2+3⁢x+1superscriptx23x1x^{2}\!+\!3x\!+\!1, x2±2⁢x+2plus-or-minussuperscriptx22x2x^{2}\!\pm\!2x\!+\!2 and x2±x+1plus-or-minussuperscriptx2x1x^{2}\!\pm\!x\!+\!1 are irreducible polynomials.